1. Field of the Invention
The present invention relates generally to a compound of silver nanowire with polymer, and more particularly, the present invention relates to a compound which silver metal nanostructures dispersing therein and capable of restraining the metal nanostructures from drifting.
2. Description of the Prior Art
A conductive metallic colloid is formed by adding metallic particles in a resin (e.g. epoxy resin). On the market, silver particles are commonly doped in a resin to from a conductive silver colloid. Because the conductive silver colloid is colloidal, it could be printed on various kinds of electronic products by means of screen-printing so that it is broadly used in applications. For example, the conductive silver colloid could be used to manufacture a specific circuit, a film switch, or connect two conducting circuits.
The silver particles used for doping on the market mentioned above are generally micro-sized. However, if nano-sized silver particles could be doped in a resin, the resistivity of the conductive silver colloid could be further decreased, and the quality and the yield of the film circuit screen-printed by the conductive silver colloid could be improved. Moreover, the conductive silver colloid doped with silver nanoparticles may not required high-temperature thermal treatment, so that it might be favorable for a plastic substrate which is incapable of tolerating high-temperature thermal treatment.
On the other hand, different nano-types of silver doping (e.g. silver nanoparticles or silver nanowires) could be used for adjusting the characteristics of the conductive silver colloid. For example, if nanowires are doped in a resin, because the conducting path length of electrons is lengthened and the hopping distance between the conducting islands is shortened, the electronic circuit manufactured by the conductive silver colloid will increase its conductivity.
In the prior art, there are various kinds of methods for manufacturing various types of nano-sized silver. Those methods are such as wet chemical reduction method, mechanical polishing process, thermal cracking the precursor with silver, and high energy plasma pyrolysis, etc. However, though the methods for manufacturing silver nanoparticles or silver nanowires are developed in the prior art, there are still many problems in manufacturing a conductive silver colloid doped with those nano-sized silver. For example, nano-type silver should be well dispersed in a resin to make sure the good yield of the conductive silver colloid. Therefore, how to well disperse the nano-sized silver in a resin is the key point for the researchers.
Furthermore, in the application of film switch, the conductive silver colloid still has the problem of silver drifting (if other kinds of metal nanostructure is doped, the metal nanostructure could happen to drift). The phenomenon of silver drifting is that when a bias is added to the film switch formed by the conductive silver colloid under a wet condition, the silver particle in the film switch would drift according to the electric field to form a larger particle or a dendritic structure in the film, so as to affect the electronic device to induce an extraordinary situation and even damage the electronic devices.
In the prior art, in order to avoid the effect of drifting silvers, a layer of carbon colloid is disposed on the film switch to isolate the mist so as to avoid the silver particles in the film being oxidized or drifted. However, adding the carbon colloid layer would increase the cost of the film switch and complicate the manufacture. On the other hand, the thickness of the carbon colloid layer needs precisely controlling to avoid the thick thickness resulting in the carbon colloid layer peeling off and further affect the electronic device itself.